Obtaining Vehicle Traffic Information Using Mobile Bluetooth Detectors

ABSTRACT

A method and system for obtaining traffic information from mobile Bluetooth detectors is disclosed. A mobile Bluetooth detector is a device located in a moving vehicle that includes Bluetooth and GPS firmware for collecting data from Bluetooth enabled devices. The mobile Bluetooth detector transmits the collected data to a remote facility where the data is processed to generate traffic information. A pair of mobile Bluetooth detectors may be used to collect data for generating ground truth.

FIELD

The present invention relates generally to vehicle traffic, and moreparticularly, relates to using mobile Bluetooth detectors to obtainvehicle traffic information.

BACKGROUND

Bluetooth is an open wireless technology standard for exchanging dataover short distances using short length radio waves from fixed andmobile devices, creating personal area networks (PANs) with high levelsof security. A Bluetooth detector is a device that can read and recordthe unique Media Access Control (MAC) address of other Bluetooth devicesthat come into radio frequency range of the detector and attempt toestablish a Bluetooth connection. When equipped with a GlobalPositioning System (GPS) device, a Bluetooth detector can also recordfrom where and at what time the unique MAC address was received.

Bluetooth detectors have been placed alongside roads to monitor trafficconditions. Two stationary Bluetooth detectors placed apart from eachother alongside a road may observe a vehicle containing a detectableBluetooth device at two different times. Each detector logs the MACaddress of the device in the vehicle and the time of detection. Thisinformation may be used to calculate a travel time and speed for adetected vehicle to travel on the road between the two detectors.

While the traffic information obtained from these statically locatedBluetooth detectors is useful, the information is limited to just theroad located between the detectors. Due to the costs involved withinstalling and maintaining the Bluetooth detector equipment, it isunlikely that Bluetooth detectors will be deployed alongside roadways ina manner sufficient to cover large portions of a road network. Thus, itwould be beneficial to obtain traffic information from Bluetoothdetectors in another manner.

SUMMARY

A method and system for obtaining traffic information from mobileBluetooth detectors is disclosed. A mobile Bluetooth detector is locatedin a moving vehicle. The detector includes a positioning system (e.g., aGPS system) that detects the location (e.g., latitude and longitude) ofthe vehicle. The detector also includes a processor that executesmachine language instructions stored in data storage to collect dataregarding Bluetooth enabled devices attempting to connect with themobile Bluetooth detector. The detector also includes a communicationmodule that transmits the collected data to a remote facility thatgenerates traffic information.

The method for obtaining traffic information from mobile Bluetoothdetectors includes providing a first device in a first vehicle moving ina geographic area. The first device has Bluetooth and GPS capabilities.The method further includes collecting data regarding other devicesattempting to connect with the first device. The other devices arelocated near the first device (i.e., within Bluetooth transmissionrange). The collected data includes when and where the other devicesattempted to connect with the first device. The method also includestransmitting the collected data to a remote facility to generate trafficinformation.

The remote facility merges the data received from Bluetooth detectors bytimestamp and MAC address, and uses map matching to generate trafficinformation from the merged data. The traffic information may includetraffic speeds and travel times of the detected devices. When a pair ofmobile Bluetooth detectors is used to collect data from Bluetoothenabled devices traveling on the same road in a direction opposite fromthe detector pair, the traffic information may be used as ground truthfor testing the accuracy of traffic systems.

These as well as other aspects and advantages will become apparent tothose of ordinary skill in the art by reading the following detaileddescription, with reference where appropriate to the accompanyingdrawings. Further, it is understood that this summary is merely anexample and is not intended to limit the scope of the invention asclaimed.

BRIEF DESCRIPTION OF THE DRAWINGS

Presently preferred embodiments are described below in conjunction withthe appended drawing figures, wherein like reference numerals refer tolike elements in the various figures, and wherein:

FIG. 1 depicts a portion of a road, according to an example;

FIG. 2 is a simplified block diagram of a Bluetooth detector, accordingto an example;

FIG. 3 is a flow chart of a method for obtaining traffic informationusing mobile Bluetooth detectors, according to an example;

FIG. 4 depicts logs from two Bluetooth detectors, according to anexample; and

FIG. 5 depicts processed Bluetooth detector log data from the logsdepicted in FIG. 4, according to an example.

DETAILED DESCRIPTION

FIG. 1 depicts a road 100 that is part of a road network in a geographicarea. Four vehicles 102-108 are depicted as traveling on the road 100.Two vehicles 102, 104 are traveling in one direction as denoted by anarrow, and the other two vehicles 106, 108 are traveling in the oppositedirection also denoted by an arrow.

Each of the vehicles 102-108 may include a device 112-118 with Bluetoothcapability. Bluetooth devices include some mobile telephones, navigationsystems, headsets, watches, cameras, PDAs, music players, and so on. Thedevices 112-118 may also include GPS capability. The devices 112-118that include both Bluetooth and GPS capability may be used as a mobileBluetooth detector. For example, many types of mobile telephones may beused as a mobile Bluetooth detector.

While the vehicles 102-108 are shown as cars, trucks, and buses, thevehicles 102-108 may also be motorcycles, bicycles, carts, and any otherstructures used for transporting people or goods. Vehicles, such astrains and boats, not associated with the road 100 may also be used totransport Bluetooth detectors. Additionally, pedestrians may transportBluetooth detectors. Thus, the term “vehicle” as used herein is intendedto cover any thing or person that can move a Bluetooth detector in ageographic area.

Moreover, it is understood that the vehicles may temporarily stop (e.g.,at a stop sign, traffic light, railroad crossing) and still beconsidered to be a moving vehicle. Thus, the term “mobile” as usedherein means that the vehicle is not fixed in a permanent or long termposition.

FIG. 2 is a simplified block diagram of a mobile Bluetooth detector 200that may be included as part of the devices 112-118. The Bluetoothdetector 200 may be a combination of hardware, software, and firmwarecomponents. The Bluetooth detector 200 includes a processor 202 and adata storage device 204. The processor 202 may be a general purposeprocessor or a special purpose processor (e.g., digital signalprocessor). The data storage device 204 may be one or more memorymodules that contain software programs, data stores, and otherelectronic information. For example, the processor 202 may executecomputer-readable program instructions contained in the data storagedevice 204.

The data storage device 204 may also contain firmware (and/or software)providing Bluetooth and GPS capabilities. Bluetooth and GPS capabilitiesare already built into many cellular phones as part of the cell phone'soperating system or application suite. The same is true for manypersonal navigation devices used by consumers for routing andnavigation. The Bluetooth firmware records the MAC addresses and time ofreception or detection for each MAC address of all other Bluetoothenabled devices attempting a connection, and saves this information in alog. The GPS firmware records the GPS location and time, and saves thisdata in a log. Both logs are also stored in the data storage device 204.

The Bluetooth detector 200 also includes a positioning system 206 thatdetermines location. The positioning system 206 may utilize GPS-typetechnology. The positioning system 206 may also include sensing devicesthat measure traveling distance, speed, direction, orientation, and soon. The positioning system 206 outputs a signal to the processor 202.

The Bluetooth detector 200 also includes a communication module 208. Thecommunication module 208 is operable to transmit data to and receivedata from a remote device. For example the data may be voice, text, ormultimedia data. The remote device may be another mobile Bluetoothdetector, a computer, or another type of device.

The Bluetooth detector 200 may also include a user interface 210. Theuser interface 210 may include a keypad having one or more keys (e.g.,switches) that are operable to input data into the detector 200. Asanother example, the user interface 210 may include a microphone andassociated electronic circuitry that are operable to input data into theBluetooth detector 200. The user interface 210 also allows an end userto obtain information from the Bluetooth detector 200.

As the mobile Bluetooth detector 200 moves along the road 100 in one ofthe vehicles 102-108, the Bluetooth detector 200 may detect otherBluetooth enabled devices. To detect other Bluetooth enabled devices,the devices are within the Bluetooth transmission range of the Bluetoothdetector 200. While class 1 Bluetooth devices currently have atransmission range up to 100 meters, it is expected that the range willincrease over time. The Bluetooth enabled devices may be moving orstationary.

When the Bluetooth detector 200 detects a Bluetooth enabled device, theBluetooth detector 200 logs the MAC address of the other device and dataassociated with when the Bluetooth detector 200 detected the otherdevice. The Bluetooth detector 200 also logs data associated with wherethe Bluetooth detector 200 detected the other device. The Bluetoothdetector 200 may also log other data regarding the detected device, suchas device attributes, which provide generic information regarding thedetected device. The device attributes may be used in filtering data,identifying vehicles, and/or classifying the detected device.

The communication module 208 transmits the Bluetooth log, the GPS log,and the MAC address of the Bluetooth detector 200 to a central facility110 for processing. The communication module 208 may also transmit otherdata, such as the device attributes, to the central facility 110. TheMAC address of the Bluetooth detector 200 identifies the unique sourceof the data. Alternatively, the communication module 208 may transmit aunique identifier other than the MAC address. This unique identifier maybe anonymous for security purposes.

The central facility 110 includes a server 120. The server 120 is acomputing platform that includes a combination of hardware, software,and/or firmware. For example, the server 120 may include a processor,memory, and a communication system. The communication system receivesthe GPS and Bluetooth logs, MAC address, and possibly other data fromthe Bluetooth detector 200 and stores the received data in the memory.

The processor in the server 120 then analyzes the data in the logs togenerate traffic information. The traffic information may includetraffic speeds and travel times. The traffic information may alsoinclude ground truth. Ground truth is used to verify the quality andaccuracy of traffic data. Ground truth data is typically collected bytrained drivers in test vehicles equipped with accurate GPS devices thatcollect the average speeds of the vehicles on the road at the samelocation as the test vehicle. However, test vehicles are expensive,collect limited test data, and are less suitable for testing roadwaysthat have traffic controls due to the number of test vehicles needed toaccurately measure average conditions in a variable environment.

FIG. 3 is a flow chart of a method 300 for obtaining traffic informationusing mobile Bluetooth detectors. At block 302, mobile Bluetoothdetectors collect Bluetooth and GPS data. For example, the devices 112,114 within the vehicles 102, 104 may be mobile Bluetooth detectors. Inthis example, the devices 112, 114 may detect the Bluetooth enableddevices 116, 118 as the vehicles 102, 104 pass the vehicles 106, 108traveling on the opposite side of the road 100.

The mobile Bluetooth detectors 112, 114 log the collected data. TheBluetooth detectors 112, 114 include hardware, software, and/or firmwareto record the MAC addresses and time of reception for each of the MACaddresses in a Bluetooth log. In addition, the detectors 112, 114include hardware, software, and/or firmware to record the GPS locationand time in a GPS log.

FIG. 4 depicts example logs 402, 404. While FIG. 4 depicts two logs, itis understood that many detectors may generate many logs. The logs 402,404 include a Bluetooth log and a GPS log. The log 402 may be a loggenerated by the Bluetooth detector 112 and the log 404 may be a loggenerated by the Bluetooth detector 114. In this example, macaddr1 isthe MAC address for Bluetooth detector 112 and macaddr2 is the MACaddress for Bluetooth detector 114.

The Bluetooth detector 112 detected the MAC address for device A at date1 and time 1 when the Bluetooth detector 112 was located at location W.The Bluetooth detector 112 detected the MAC address for device B at date1 and time 2 when the Bluetooth detector 112 was located at location X.The Bluetooth detector 114 detected the MAC address for device A at date1 and time 3 when the Bluetooth detector 114 was located at location Y.The Bluetooth detector 114 detected the MAC address for device B at date1 and time 4 when the Bluetooth detector 114 was located at location Z.

Returning to FIG. 3, at block 304, the mobile Bluetooth detectorstransmit the collected data to a central facility. For example, theBluetooth detector 112 may transmit the log 402 along with thedetector's MAC address (i.e., macaddr1) to the central facility 110 andthe Bluetooth detector 114 may transmit the log 404 along with thedetector's MAC address (i.e., macaddr2) to the central facility 110. Themobile Bluetooth detectors 112, 114 may transmit the data at regulartime or travel distance intervals. Alternatively, the mobile Bluetoothdetectors 112, 114 may transmit the data continuously or based on aschedule, a triggering event, or at any other time.

At block 306, the server 120 at the central facility 110 generatestraffic information from the received data. After receiving the data,the server 120 merges the data from the logs 402, 404 by timestamp andMAC address, and stores the merged data into a database. For example,FIG. 5 depicts merged data 500 from the logs 402, 404.

With the merged data 500, the server 120 determines that the Bluetoothenabled device associated with macaddrA traveled from location W tolocation Y between times 1 and 3 on date 1. Similarly, the server 120determines that the Bluetooth enabled device associated with macaddrBtraveled from location X to location Z between times 2 and 4 on the sameday.

The server 120 performs map matching of the merged data 500 to generatetraffic speeds and travel times. Map matching compares outputs from apositioning system (e.g., a GPS system) with digital map data in ageographic database to determine the most likely location of thepositioning system on the digital map. The server 120 may include ageographic database stored in memory to perform the map matching.Alternatively, the server 120 may use the communication system to accessa geographic database located remote from the server 120. The geographicdatabase may be a geographic database published by NAVTEQ North America,LLC of Chicago, Ill.

The server 120 may filter the merged data 500 prior to analyzing thedata to generate traffic information. For example, not all Bluetoothenabled devices are located in a vehicle traveling on a road network.During map matching, the server 120 may determine whether the Bluetoothdetector 200 is in a vehicle moving on the road network. Bluetoothsignals from pedestrians, households, and other non-vehicular Bluetoothdevices may be removed from the merged data 500. Bluetooth signals fromvehicles not traveling on a roadway, such as trains and boats, may alsobe removed from the merged data 500. The additional device attributeslogged at the time of detection may assist in classifying the detecteddevices as being located in a vehicle.

To remove Bluetooth signals from the merged data 500, the server 120 maycompare detections from macaddrA and macaddrB with reference to thelocations and times for macaddr1 and macaddr2 to determine if macaddrAand macaddrB “act” like vehicles moving along a roadway. In other words,the server 120 processes the data collected by macaddr1 and macaddr2into logical vehicle speeds along a roadway path. In order to do this,the server 120 determines the speed and direction of macaddrA andmacaddrB over time. The server 120 determines if the speeds are logicalvehicle speeds and direction of travel indicate a general roadway path.If the locations for macaddr1 and macaddr2 are on a roadway traveling inthe same direction, the data for macaddrA and macaddrB may show traveltimes and speeds in the opposite direction from macaddr1 and macaddr2.

If macaddrA and macaddrB are stopped or moving slowly, the server 120looks for higher speeds at a previous time along the roadway. If recentfaster speeds along the roadway are known, then the slower speeds can beretained. If no high speed data is seen from macaddrA or macaddrB, thenthe data from these devices may be removed from the merged data 500because this data may not be vehicular data.

To distinguish stopped vehicles from pedestrians, the server 120 maydevelop a profile of speeds and map matched roadway locations for eachMAC address detected by a series of Bluetooth detectors. The profiles ofdetected Bluetooth devices create a picture of what is happening on theroadway. For example, if one detected Bluetooth device is stopped (e.g.,a pedestrian or a disabled vehicle) and the other detected devicesaround the stopped device indicate movement on the roadway, then thedata from stopped device may be removed from the merged data 500.

As previously mentioned, the mobile Bluetooth detector 200 may also beused to create a ground truth for testing roadways. For ground truth, apair of Bluetooth detectors 200 separated by a variable distance andtraveling in the same direction on the same roadway is used to determinethe speeds or travel times of vehicles containing Bluetooth enableddevices traveling in the opposite direction on the same roadway.Preferably, the distance between the Bluetooth detectors is between oneand five miles; however, other distances may be used. The mobileBluetooth collection pairs (e.g., detectors 112, 114) can log andmeasure many ground truth samples from the Bluetooth enabled devices invehicles traveling in the opposite direction on the same roadway (e.g.,devices 116, 118). The remote facility 110 may provide the trafficinformation to businesses providing a traffic service (i.e., B2B) and/orconsumers using various traffic enabled devices, such as a navigationsystem (i.e., B2C). For example, a traffic data supplier may provide thetraffic information in the form of one or more data feeds, such as anRSS or XML feed.

Mobile Bluetooth detectors overcome the problems with static Bluetoothdetectors and test vehicles. The mobile Bluetooth detectors providelarge volumes of floating car data (FCD), which allows traffic datasuppliers to generate traffic information with reduced cost and expandedcoverage. Moreover, the traffic data suppliers may use pairs of mobileBluetooth detectors to accurately test vehicle speeds on all types ofroads at a reduced cost.

It is intended that the foregoing detailed description be regarded asillustrative rather than limiting and that it is understood that thefollowing claims including all equivalents are intended to define thescope of the invention. The claims should not be read as limited to thedescribed order or elements unless stated to that effect. Therefore, allembodiments that come within the scope and spirit of the followingclaims and equivalents thereto are claimed as the invention.

We claim:
 1. A method comprising: receiving location data for aplurality of wireless devices; receiving data indicative of connectionattempts for the plurality of wireless devices; storing the locationdata in a location log; storing the data indicative of connectionattempts in a connection log; and generating traffic data based on thelocation log and the connection log.
 2. The method of claim 1, furthercomprising: providing travel times or traffic speeds based on thetraffic data.
 3. The method of claim 1, further comprising: comparingthe location data to map data from a geographic database; and matchingthe location data to a location in the map data.
 4. The method of claim3, further comprising: filtering at least one of the plurality ofwireless devices when the location data is not on a roadway.
 5. Themethod of claim 4, wherein the filtered at least one of the plurality ofwireless devices corresponds to a boat or a train.
 6. The method ofclaim 1, further comprising: comparing the location data for each of theplurality of wireless devices to a range of speeds; and filtering thelocation data outside of the range of speeds.
 7. The method of claim 6,wherein the filtered location data corresponds to a pedestrian, or adisabled vehicle.
 8. The method of claim 1, wherein the location logdistinguishes between the plurality of wireless devices using mediaaccess control (MAC) addresses.
 9. An apparatus comprising: at least oneprocessor; and at least one memory including computer program code forone or more programs; the at least one memory and the computer programcode configured to, with the at least one processor, cause the apparatusto at least perform: receive location data for a plurality of wirelessdevices; receive data indicative of connection attempts for theplurality of wireless devices; store the location data in a locationlog; store the data indicative of connection attempts in a connectionlog; and generate traffic data based on the location log and theconnection log.
 10. The apparatus of claim 9, further comprising:provide travel times or traffic speeds based on the traffic data. 11.The apparatus of claim 9, further comprising: compare the location datato map data from a geographic database; and match the location data to alocation in the map data.
 12. The apparatus of claim 11, furthercomprising: filter at least one of the plurality of wireless deviceswhen the location data is not on a roadway.
 13. The apparatus of claim12, wherein the filtered at least one of the plurality of wirelessdevices corresponds to a boat or a train.
 14. The apparatus of claim 12,further comprising: compare the location data for each of the pluralityof wireless devices to a range of speeds; and filter the location dataoutside of the range of speeds.
 15. The apparatus of claim 14, whereinthe filtered location data corresponds to a pedestrian, or a disabledvehicle.
 16. The apparatus of claim 9, wherein the location logdistinguishes between the plurality of wireless devices using mediaaccess control (MAC) addresses.
 17. A non-transitory computer readablemedium configured to store instructions, executable by a processor, toperform: receiving location data for a plurality of wireless devices;receiving data indicative of connection attempts for the plurality ofwireless devices; comparing the location data to a predetermined map;comparing the location data to a speed profile; filtering the locationdata according to the speed profile or the predetermined map; andgenerating traffic data based on the location data and the dataindicative of connection attempts.
 18. The non-transitory computerreadable medium of claim 17, the instructions further configured toperform: storing the location data in a location log; and storing thedata indicative of connection attempts in a connection log.
 19. Thenon-transitory computer readable medium of claim 17, wherein thefiltered location data corresponds to location outside of a roadway. 20.The non-transitory computer readable medium of claim 17, wherein thefiltered location data corresponds to a pedestrian, a train, a boat, ora disabled vehicle.